What is the effect of the simile "The blackboard is like a battle zone. / The answers have fallen victim?"
A.
to show that the teacher wants all the answers to be incorrect
B.
to show that the students have wrestled in front of the blackboard
C.
to show that the students have tried hard to solve the question
D.
to show the teacher acting like a cruel astronomy general

C.  to show that the students have tried hard to solve the question.

Explanation:

The term "battle zone" symbolizes the situation in which the students try as hard as they can to answer the questions. They are trying to 'fight' the questions - solving the questions means "victory."

Option A is incorrect, as there is unlikely a teacher that would want the students to give incorrect answers. Moreover,  the students certainly have not wrestled in front of the board, nor has the teacher acted as a cruel general. The meaning of this simile should not be taken literally.